THE PERFORMANCE OF DAIRY AND FEEDLOT CATTLE FED SULFUR DIOXIDE-TREATED HIGH-MOISTURE BARLEY

Abstract

Two experiments were conducted to determine the influence of feeding sulfur dioxide (SO2)-treated high-moisture barley (HMB) on the performance of lactating dairy cows and feedlot cattle. High-moisture barley was ensiled or treated with 1% (wt/wt) liquid SO2. In exp. 1, 36 lactating Holstein cows were assigned to three treatments for a 6-wk trial. Diets contained 35% rolled barley on a dry matter (DM) basis and differed only in the type of barley fed: dry barley, ensiled HMB or SO2-treated HMB. While no differences (P > 0.05) were observed in DM intake, milk yield, milk composition, milk taste or odour, cows fed SO2-treated HMB tended to have lower milk yield (21.7 kg d−1) than those fed ensiled (22.6 kg d−1) or dry barley (24.6 kg d−1). In experiment 2, 64 steers were allotted to four dietary treatments: (1) dry barley, (2) ensiled HMB, (3) SO2-treated HMB, and (4) SO2-treated HMB plus sodium bicarbonate. All diets contained 85% barley (DM) and were supplemented with thiamin (5.5 mg kg−1 DM). The results of the feedlot trial were confounded by the feeding of spoiled SO2-treated HMB, primarily between days 29 and 57 of the 96-d trial, at approximately 40% of the diet DM. During the period that spoiled SO2-treated grain was being fed, four steers (two from each treatment) developed polioencephalomalacia. Steers fed SO2-treated HMB (diets 3 and 4), had 10.1% lower DM intake (P < 0.01), 31% lower average daily gain and required 32% more DM per kilogram of gain than steers fed diets 1 or 2 (P < 0.001). Feeding SO2-treated HMB to either dairy or feedlot cattle cannot be recommended at the present time. Key words: Sulfur dioxide, preservative, barley, cattle (dairy, beef)